Karaköy bridge with Yeni (New) Mosque. Blue Mosque on the top of the skyline.The outside of the Hagia Sophia, the 6th century church which was, with the Muslim takeover of Constantinople, converted first to a mosque, then a museum.Ortaköy Mosque, which was built in the middle of the 19th century. Bosporus bridge in the back, connecting Europe an Asia.Topkapi Palace, home of the Ottomansultans and their harems.

Largest city in Turkey with 8,8 million inhabitants (1996 estimate, within municipal borders), situated on both sides of the Bosporus, making Istanbul a city of two continents, Europe and Asia. It is the capital of Istanbul province with 10 million inhabitants (2004 estimate).The name "Istanbul" comes from the Greek phrase "eis ten polin" used by Constantinople's inhabitants, and which meant "in the city". The Arabs adopted it and used it as a name for the city, Istinbolin.There are 3 major parts of Istanbul. On the European side lies Stamboul and Beyoglu, divided by the Golden Horn a drowned valley about 7 km long. On the Asian side lies Üsküdar (ancient Chrysopolis) and Kadiköy (ancient Chalcedon). Larger Istanbul is 45 km wide and 35 long from south to north. The city continues all along the strait of Bosporus, which connects the Black Sea to Sea of Marmara and the Mediterranean further south.The original Constantinople was surrounded by seven hills, just like Rome. 6 crests lies along the Golden Horn, while the 7th lies alone about a km south. The hills have plat summits, and steep slopes. This, the original part of the city. now corresponds to Stamboul, which is the main focus of tourism, with the many sights from the city's long history.Beyoglu is the modern part of today's Istanbul, housing many theatres, government offices and businesses.The waters from the Black Sea thrust south through the Bosporus. Underneath there is strong undercurrent coming from the Mediterranean Sea. The currents change 7 times through the strait, often making it difficult to pass for smaller vessels.Istanbul is connected to Europe and the rest of Turkey with highways and railroads. The bridges crossing the Bosporus are among the longest highway suspension bridges in the world. Istanbul's airport is called Yesilköy International Airport, and lies 27 west of the city.The climate of Istanbul is subtropical, with summer average summer temperatures of 28°C and winter average of 8°C. Annual precipitation is around 800 mm, enough to make the city green and the surrounding areas rich in agriculture.The largest and culturally and historically most important part lies in Europe, while the richest part lies in Asia.

Economy
About 35% of Turkey's manufacturing plants are located to the area around Istanbul. The city is the chief seaport as well as the commercial and financial centre of Turkey.A large scale of industries are found here: automobile and truck assembly, shipbuilding and ship repairing; cement production, cigarettes; food products, fruit, olive oil, silk; glass, cotton, leather, pottery and more.Istanbul is also an important centre for banking and insurance. Another important source of income for the city is tourism.

Culture
Constantinople was for centuries one of the most important cities in the world. When the decline of Rome, Constantinople took over as the leading city. It allowed for a fusion of several cultures, in customs, art and architecture. The coin of Constantinople, solidus, was the dominating monetary standard of its time.Istanbul has a wide range of sights of great historical and cultural interest. There are many churches preserved in the city, many have been converted into mosques.Hagia Sophia
The Hagia Sophia was originally a church, but was converted into a mosque in 1453, and in 1932 into a museum. It is now known as Aya Sophia, and lies near the Sea of Marmara in the Stamboul quarters.The church was erected in the 6th century by the architects Arthemius of Tralles and Isidore of Miletus. The dome, 33 metre wide, was among the most ambitious building projects of pre-Medieval times. The dome was completed within a period of 5 years. It would take 10 centuries before any architects dared to challenge its size, but then without full success.But it would take only 20 years after its completion before serious weaknesses with the construction became evident. An earthquake made central parts of the dome collapse, and a nephew of Isidore of Miletus, called Isidorus the Younger, made changes. Among the changes were to close several of the windows, resulting in the dim half-light that characterize the building even today.While the conversion of the church to a mosque in the 15th century was hard enough, it was Crusaders in 1203 who made themselves guilty of the worst case of desecration Hagia Sophia ever saw. The tore up the altar, all valuables were taken away and a prostitute was placed on the patriarch's chair, while the hymns and processions of the eastern church were ridiculed.Topkapi Palace
This palace, situated on the tip of old Constantinople, was the political centre of the Ottoman Empire for 4 centuries. Large parts of the palace were devoted to offices and state institutions as well as a palace school. Only about half was the residence of the sultan and his harem. The harem women counted as many as 809 during the reign of Sultan Abdülaziz in the late 19th century.The palace was built between 1459 and 1465, but was in the beginning not the residence of the sultan. He stayed in his palace where the Istanbul University now is located, together with his harem. Later on all this moved into the Topkapi, but in the middle of the 19th century, a new palace was constructed a few kilometres further up the Bosporus.Blue Mosque
Built next to the 1000 year older Hagia Sophia, the Blue Mosque, or Sultan Ahmet mosque, was intended to challenge the grandeur of Christian Constantinopian architecture. It didn't succeed.The Blue Mosque is beautiful from the outside, but the interior tells stories about crude building engineering and the decorations are not up to the standard found elsewhere in the Muslim world.The becoming of the Blue Mosque was difficult. Its 6 planned minarets was by many considered unholy, as it challenged the mosque in Madina where Muhammad is buried. Moreover, many palaces of imperial minsters were sacrificed to give room. The ministers claimed that the empire couldn't afford the building of the mosque, but they all had to give in in the end.

HistoryEnd of 8th century BCE: Founded as a Greek trading colony.657: The legendary foundation of the city, by the Greek warlord Byzas. Byzas came from the city of Megara and captured the peninsula from Thracian tribes.512: The Greek colony passes on to the Persian king Darius 1.478: Captured by an Athenian fleet, and becomes part of the Delian League.420's: Byzantium transfers its allegiance to Sparta.343: Byzantium transfers its allegiance to the Second Athenian League.340: Is besieged by the Macedonian king Philip.Around 333: Byzantium becomes subject to Alexander the Great.2nd century: The city is ruined after buying off marauding Gauls.70's CE: Falls under the domination of the emperor of Rome.196: The Roman Emperor Septimus Severus razes Byzantium as a revenge of the city' support for his opponent, Pescennius Niger, during civil war in the empire. He had it rebuilt on a larger scale, and renamed August Antonina in honour of his son.268: Byzantium is sacked by Gallenius.324 September 18: Constantine 1 makes Byzantium his capital, naming it Roma Nova (New Rome).330 May 11: Roma Nova becomes the seat of the Roman Empire, and is named after Constantine the Great, into Constaninople.381: A patriarchate is established in Constantinople, second only to the Pope in Rome.Early 5th century: New city walls are erected, and are the ones surviving until modern times.532: Large parts of the city is burned and about 30,000 of the population is killed during a repression of an insurrection.537: The Hagia Sophia church is completed, the most magnificent building of its time.542: A plague kills about 75% of the inhabitants of Constantinople. The effects were devastating, and weakened the city and the Byzantine Empire for 300 years.626: Is besieged by Persians and Avars, but withstands.674: Is besieged by Muslim Arabs, a siege that would last for 5 years, but without the fall of Constantinople.717: A second siege by Muslim Arabs, this time lasting 2 years, but again without the fall of Constantinople.813: Bulgars besiege Constantinople, but it withstands.813: Russians besiege Constantinople, but it withstands.913: Bulgars besiege Constantinople for a second time, but the city withstands.941: Russians besiege Constantinople for a second time, but it withstands.1043: Russians besiege Constantinople, but it withstands again.1054: The Great Schism divides Christendom in an western and eastern part, with Constantinople as centre of the eastern.1090: Turkic Pechengs try to conquer Constantinople, but without success.1203: Captured by the armies of the 4th Crusade, but the city remained under its own rule.1204 April 13: Crusaders burst into Constantinople, and sacks the city, and plunders all its wealth. They established a Latin rule, while the Byzantine Empire continued to exist with its capital in Nicaea 100 km southeast.1261: Constantinople is conquered by Michael 8 Palaeologus, and reestablished as capital of the Byzantine Empire.1422: Ottoman sultan Murad 2 lays a siege on Constantinople.1452: Sultan Mehmed 2 lays Constantinople under siege, and erects a strong fortress at Rumeli Hisari effectively blocking the strait of Bosporus.1453 May 29: Constantinople is captured by Ottoman troops, and is quickly turned into capital of the empire. The city was pillaged and its inhabitants massacred for 3 days, before order was established by the sultan.
 Istanbul University is established.1773: The Technical University is established.1856: The residence of the sultan is moved from Topkapi palace to the new Dolmabahce palace further up the Bosporus.1863: The American Colleges is established, later renamed University of the Bosporus.1883: The Marmara University and Mimar Sinan University are established.1911: The Yildiz University is established.1918: Following the defeat of the Ottoman Empire in the World War 1, British, French and Italian troops occupies Constantinople.1923: With the fall of the Ottoman Empire and establishment of Turkey, Constantinople is returned to Turkish control but the capital of the new state becomes Ankara.1930: Constantinople changes its name officially into Istanbul. Istanbul had been the popular name of the city for 5 centuries already.1970: Huge works with infrastructure are carried through, with new roads, bridges and a tramway.1980: A conservation programme for the architecture is started.2003 November: Bombings in Istanbul, killing more than 60 people. Two were launched outside synagogues.